Contamination concerns represent the most common subtype of obsessive-compulsive disorder (OCD). Although traditionally conceptualized as a fear-based disorder, recent theoretical models suggest that disgust may play a crucial role in contamination-based OCD's etiology and maintenance. Numerous studies show that disgust sensitivity--how easily and intensely one experiences disgust--uniquely predicts symptom severity. However, a mechanism explaining this relationship has been elusive. In light of recent evidence that attentional biases are causal in anxiety disorders, this project will investigate the possibility that disgust sensitivity confers vulnerability to contamination-based OCD by facilitating attentional biases. To examine the effects of disgust sensitivity, experienced disgust will be manipulated in patients and controls, and effects on visual processing of contamination will be assessed using state-of-the-art eye tracking technology. Psychophysiological measures will be used to assess disgust responding, and a public restroom behavioral avoidance task will be used to assess behavioral effects of the mood induction. A mediational model will be tested, in which disgust increases behavioral avoidance by inducing attentional biases for contamination.